Future proofing is relative. RTF and docx are decipherable enough by observation. The format we really don’t want to disappear is zip.
Rename a .docx or .xlsx file to .zip, unzip it, and it is little trouble reading or extracting text from the XML revealed in the zip.
Reverse engineering zip is obviously possible but not trivial if all you have are example zip files with unknown content.
If high school kids can knock out a quick script to extract text from a document, that’s future proof enough for my individual purposes.
Just always make sure you can easily understand your data without your apps. Of course, that’s just me and my need to freely interpret information.
“BIQHa’DIbaH qeylIS Degh,” as they say so clearly in the Klingon Empire (“mileage varies”).
